The invention relates to electric connecting means employed in low-voltage electrical engineering, more particularly in electronics and telecommunications. These connecting means are usually multi-polar and may, for example, be multi-polar connectors and sockets, the connecting members of these connecting means have very frequently been made of a base metal, such as phosphor-bronze, having a 1 to 3 .mu.m thick gold layer on the contact areas. The gold layer must be sufficiently resistant to wear, in order to be able to withstand 100 to 500 contacting operations, without local removal of the coating due to wear. This is accomplished by using alloyed gold in combination with base metal elements. A frequently used alloy is applied by means of a rolling operation to form a contact layer having a composition (in % by weight) of 70--Ag 20--Cu 10 or Au 70--Ag 24--Cu 6. However, an oxide layer forms at the surface since base metal elements are present in the alloy. This is disadvantageous, particularly at elevated temperatures, as then the oxide layer may become so thick that the contact resistance increases considerably. The formation of oxide layers on alloyed gold can be counteracted by applying a thin (for example 0.2 .mu.m) layer of pure, unalloyed gold on top of the alloyed gold layer.
A different, known construction is a contact having a wear-resistant hard layer consisting of gold alloyed with, for example, cobalt, this layer having been deposited electrolytically.
However, gold is becoming rare and expensive so that it is an absolute necessity to use it as sparingly as possible.
When gold is deposited in a layer less than 1 .mu.m thick, it is porous and does not withstand the corrosion test in which the relevant object is exposed for 24 hours to an atmosphere containing 1% by volume of SO.sub.2 and 1% by volume of H.sub.2 S and having a relative humidity at room temperature of about 90%. (Proposal 130 of the International Electrotechnical Committee.